In the opening sequence of this episode, 'the Observer' receives a United States flag lapel pin from a veteran. Then it disappears and reappears several times between shots.
When a shot of The Observer's message decoded by Walter is shown, the symbol for "As" is identical to "N" and the symbol for "Ti" is identical to "Ge".
In the long shot of Olivia on the roller coaster, it is clearly someone wearing a poor blonde wig, and not the actual actress.
Between 1:26 and (at 2:02 the pin is not on the lapel) 2:08, a veteran taking collections in the park adds a flag pin the the lapel of an Observer (known as August) where it momentarily is missing from one shot to the next and then is back again as it should be.
The news reader states the plane crashed in the Atlantic ocean, two hours outside of Rome. Peter later tells Walter that the plane crashed off the coast of Italy, which would have put it in the Mediterranean, not the Atlantic.
Even though the show is supposed to take place in Boston, MA, you can see that it is filmed in Canada when a large Canadian flag is visible in the closing sequence at the amusement park just as Olivia and her niece are starting their roller coaster ride. It is very obvious this is shot at Playland in Vancouver, BC.
Walter tells the Fringe team that the Naga Jolokia peppers would have to be imported because they could not be grown locally. This is incorrect. While they are native to India and do better naturally in a hot and humid environment, they can be cultivated and grown practically anywhere by someone with the knowledge and the means to do so.